A local archaeologist says there may be the remains of a historic Alutiiq fish trap on the north end of Kodiak Island.

Those types of man-made formations are rare to discover in the region, he said.

The Alutiiq Museum is in its second year of documenting ancestral sites on Afognak Native Corporation lands. Museum archaeology curator

Patrick Saltonstall noticed something while surveying one area on the shoreline at low tide.

He identified it as a fish trap, which he calls a corral.

“They’re like stone walls on the inter-tidal zone so when the tide came in, all the fish went to go up stream, would float in over the corrals or the trap, and then when the tide went out, they’d be stranded in the pens, so then you catch a whole lot of fish.”

He says it can be challenging to determine whether a corral is natural or man-made, but he sees evidence of it being a fish trap.

“I could tell that there were some boulders that they used that there were there already, but almost all of it was bringing boulders in,” he said. “It’s like a wall, like 5 feet across and maybe 2 feet high now, but it was probably much higher (back) in the day.”

corral like this one on the island, but they’re common in southeast, which he said could because the people there used them more frequently.

“A lot of the places down there are more protected, they aren’t as open to the ocean as Kodiak is, so maybe the lower energy they tend to be preserved better,” he said. “Whereas in Kodiak after a big storm a lot of these things might get demolished.”

Archaeologists found what looks like petroglyphs nearby, he said, speckled dots and incised lines carved into slate.

“What the cool pattern is is they all seem to be associated with fishing localities,” Saltonstall said. “You look at the typical petroglyphs, you know with faces, whales, drummer, they’re associated more with whaling or with villages.”

It’s hard to determine the age of either the corral or the petroglyphs, but based on nearby archaeological sites, the carvings could be dated back to about 500 years ago.

SAKURAI, Nara Prefecture–Thousands of peach pits found near building ruins in the Makimuku archeological site in western Japan were likely harvested between 135 and 230 A.D., adding to the possibility that the ancient kingdom called Yamataikoku was located here.

The results of carbon-14 dating of the ancient seeds were published in the latest issue of the bulletin of the Research Center of the Makimukugaku, Sakurai City.

According to the research center of the Makimukugaku, about 2,800 peach seeds were found from a pit about 5 meters south of the site of the building in 2010 along with other items, including parts of baskets and potteries, and many plants and animal bones. The objects found in the pit were believed to have been buried after being used in some kind of rituals.

The archeological site, stretching over a large area around JR’s Makimuku Station, is a government-designated historic site dating from the early third to early fourth century. It is one of the few sites around Japan that is believed to be the location of the elusive kingdom of Yamataikoku.

The kingdom appears in “Gishiwajinden,” a history book of ancient China, and is said to have existed from the end of the second century through the first half of the third century until the death of queen Himiko, who co-reigned over a greater nation called Wa, which covers much of today’s Japan.

Where Yamataikoku was located has divided Japanese historians and scholars into two camps–either in Kyushu island or in the Kinki region, where Nara Prefecture is located.

“The dates derived by scientific analysis fell into the range we expected,” said Kaoru Terasawa, the director of the Research Center of the Makimukugaku. “Along with the archeological analysis based on the age of potteries, the age of the large building was verified to be from the first half of the third century.”

However, Chuhei Takashima, archeologist and former dean of Saga Women’s Junior College, who believes Yamataikoku was located in Kyushu island, disagreed.

“It is still not definitely certain whether the carbon dating data actually indicates the age of the building itself,” he pointed out.

It is the first time that a natural scientific method was used to date the building’s ruins, which measures 19.2 meters north to south and 12.4 meters east to west, in the Makimuku site. The carbon dating makes it more likely than ever that it originated from around the era that Himiko ruled over Wa.

To date the pits, Yoshio Nakamura, professor emeritus of Nagoya University, and Ryo Kondo, director of social education of the education board of the Tokushima prefectural government, both conducted radiocarbon dating tests separately using accelerator mass spectrometry.

Nakano studied 15 pits, and apart from three that could not be analyzed, he concluded that 12 originated from between 135 and 230 A.D.

Kondo studied two others and obtained similar results. He also analyzed charred matter on pottery pieces and melon seeds found in the pit, and concluded they are highly like to be from between 100 and 250 A.D.

The development of agriculture in Europe not only revolutionised food acquisition, but also brought changes in the light sources our ancestors used, says archaeologist Dr. Krzysztof Tunia.

In the area of present-day Poland, until about the 5th millennium BC, to light up the darkness people used light from bonfires and probably torches in the form of wooden fins. Lighting changed with the knowledge of agriculture and farming coming from the Middle East to Europe.

Why did this happen? “Along with the more advanced farming system, the capability to manufacture a variety of ceramic vessels appeared. During excavations in Poland territory – mainly on the Baltic coast – we find not only kitchen forms, but also items that had a different function. They were probably simple lamps” – explains archaeologist from the Institute of Archaeology and Ethnology PAS Dr. Krzysztof Tunia. He refers to items in the form of shallow “baths” or “boats”. He adds that their main part was a container for flammable substance. The light was obtained by igniting a submerged plant wick.

According to the scientist, the “brightest” area in the late Mesolith and early Neolithic was the Baltic Sea zone, including the northern part of present Poland, where archaeologists find many vessels that served as lamps. The deeper inland you go on the European continent, the less light sources are found. Inland, in his opinion, was dominated by torches. These are usually not preserved to our times and archaeologists do not encounter them during excavations.

Some ceramic lamps used in Central Europe were probably suspended with strings, as their appearance indicates. These objects are cubes with a few centimetres long edges, with a depression in the middle and four holes in the corners. Other lamps were made in the form of figures of bulls, also with a recess on the back and with holes.

“These objects come from areas south of the Carpathians, but perhaps they will be also found in Poland” – says Dr. Tunia.

He adds that so far very few ceramic forms have been discovered in southern Poland, in the shape of double-cone, small vessels with holes for hanging. It can not be ruled out that they were used as lamps, Dr. Tunia believes.

“The main problem was access to flammable substances. Only by the sea there was a sufficiently large amount of available raw material for the production of combustible material used in lamps – it was the fat obtained from marine animals”. The farther south of the Baltic coast, the more common torches were. “I think that torches were not wrapped or smeared with anything, people used the natural resins in the wood material” – said Dr. Tunia.

Archaeologists, like detectives, find indirect evidence for the use of torches in prehistory. For example, during the excavations at a striped flint mine in Krzemionki Opatowskie that was active already in the Neolithic period, they found charcoal – most likely the remains of torches or fires burned there. The first possibility is more likely, because a bonfire would consume too much oxygen miners needed to breathe. Fires were burned near the bottoms of vertical shafts, where torches necessary to illuminate the darkness in the shaft would be lit up – archaeologists believe.

Lines made with charcoal, visible on mine walls, are also considered evidence of the use of torches. Dr Tunia thinks these are traces of charred tips being removed by rubbing the torch against the wall to create a larger flame.

According to the archaeologist, starting from the Neolithic period one can gradually see the desire to light up the darkness among the inhabitants of Europe, but their life was still regulated by the natural rhythm of day and night. Lighting was usually needed in places the sunlight never reached – in the mines, caves or … huts. In households, hearths and fires were being replaced by more advanced clay furnaces. They generated less smoke, they kept warm longer, but they were bad sources of light.

“The darkness was deeper still because those houses did not have many openings. It seems that the main function of a hut was to provide shelter and heat for its inhabitants, and the aspect of interior lighting – especially through openings in the walls, windows and doors – was secondary. In any case, valuable heat would escape through these holes” – says Tunia. Artificial light, even to a limited extent, was needed at any time of the day, for example to prepare a meal.

Only the outlines of prehistoric houses and their foundations or underground parts survive to our times. Reconstructing them is very difficult. It most often is based on ethnographic analogies. “And here we often see that in communities still living outside the mainstream of civilization, the huts are dark, without window openings, smoky, but providing shelter and warmth. I had the opportunity to see such houses in Andean communities” – adds the archaeologist.

According to Dr. Tunia, specialized analyses of possible ceramic lamps could bring advances in research on prehistoric lighting. “They have not been analysed so far, so it will be the next step to understanding an important aspect of our ancestors` lives” – the scientist concludes.

Of all the plants that humanity has turned into crops, none is more puzzling than the sweet potato. Indigenous people of Central and South America grew it on farms for generations, and Europeans discovered it when Christopher Columbus arrived in the Caribbean.

In the 18th century, however, Captain Cook stumbled across sweet potatoes again — over 4,000 miles away, on remote Polynesian islands. European explorers later found them elsewhere in the Pacific, from Hawaii to New Guinea.

The distribution of the plant baffled scientists. How could sweet potatoes arise from a wild ancestor and then wind up scattered across such a wide range? Was it possible that unknown explorers carried it from South America to countless Pacific islands?

An extensive analysis of sweet potato DNA, published on Thursday in Current Biology, comes to a controversial conclusion: Humans had nothing to do with it. The bulky sweet potato spread across the globe long before humans could have played a part — it’s a natural traveler.

Some agricultural experts are skeptical. “This paper does not settle the matter,” said Logan J. Kistler, the curator of archaeogenomics and archaeobotany at the Smithsonian Institution.

Alternative explanations remain on the table, because the new study didn’t provide enough evidence for exactly where sweet potatoes were first domesticated and when they arrived in the Pacific. “We still don’t have a smoking gun,” Dr. Kistler said.

The sweet potato, Ipomoea batatas, is one of the most valuable crops in the world, providing more nutrients per farmed acre than any other staple. It has sustained human communities for centuries. (In North America, it often is referred to as a yam; in fact, yams are a different species originating in Africa and Asia.)

Scientists have offered a number of theories to explain the wide distribution of I. batatas. Some scholars proposed that all sweet potatoes originated in the Americas, and that after Columbus’s voyage, they were spread by Europeans to colonies such as the Philippines. Pacific Islanders acquired the crops from there.

As it turned out, though, Pacific Islanders had been growing the crop for generations by the time Europeans showed up. On one Polynesian island, archaeologists have found sweet potato remains dating back over 700 years.

A radically different hypothesis emerged: Pacific Islanders, masters of open-ocean navigation, picked up sweet potatoes by voyaging to the Americas, long before Columbus’s arrival there. The evidence included a suggestive coincidence: In Peru, some indigenous people call the sweet potato cumara. In New Zealand, it’s kumara.

A potential link between South America and the Pacific was the inspiration for Thor Heyerdahl’s famous 1947 voyage aboard the Kon-Tiki. He built a raft, which he then successfully sailed from Peru to the Easter Islands.

Genetic evidence only complicated the picture. Examining the plant’s DNA, some researchers concluded that sweet potatoes arose only once from a wild ancestor, while other studies indicated that it happened at two different points in history.

According to the latter studies, South Americans domesticated sweet potatoes, which were then acquired by Polynesians. Central Americans domesticated a second variety that later was picked up by Europeans.

Hoping to shed light on the mystery, a team of researchers recently undertook a new study — the biggest survey of sweet potato DNA yet. And they came to a very different conclusion.

“We find very clear evidence that sweet potatoes could arrive in the Pacific by natural means,” said Pablo Muñoz-Rodríguez, a botanist at the University of Oxford. He believes the wild plants traveled thousands of miles across the Pacific without any help from humans.

Mr. Muñoz-Rodríguez and his colleagues visited museums and herbariums around the world to take samples of sweet potato varieties and wild relatives. The researchers used powerful DNA-sequencing technology to gather more genetic material from the plants than possible in earlier studies.

Their research pointed to only one wild plant as the ancestor of all sweet potatoes. The closest wild relative is a weedy flower called Ipomoea trifida that grows around the Caribbean. Its pale purple flowers look a lot like those of the sweet potato.

The ancestors of sweet potatoes split from I. trifida at least 800,000 years ago, the scientists calculated. To investigate how they arrived in the Pacific, the team headed to the Natural History Museum in London.

The leaves of sweet potatoes that Captain Cook’s crew collected in Polynesia are stored in the museum’s cabinets. The researchers cut bits of the leaves and extracted DNA from them.

The Polynesian sweet potatoes turned out to be genetically unusual — “very different from anything else,” Mr. Muñoz-Rodríguez said.

The sweet potatoes found in Polynesia split off over 111,000 years ago from all other sweet potatoes the researchers studied. Yet humans arrived in New Guinea about 50,000 years ago, and only reached remote Pacific islands in the past few thousand years.

The age of Pacific sweet potatoes made it unlikely that any humans, Spanish or Pacific Islander, carried the species from the Americas, Mr. Muñoz-Rodríguez said.

Traditionally, researchers have been skeptical that a plant like a sweet potato could travel across thousands of miles of ocean. But in recent years, scientists have turned up signs that many plants have made the voyage, floating on the water or carried in bits by birds.

Even before the sweet potato made the journey, its wild relatives traveled the Pacific, the scientists found. One species, the Hawaiian moonflower, lives only in the dry forests of Hawaii — but its closest relatives all live in Mexico.

The scientists estimate that the Hawaiian moonflower separated from its relatives — and made its journey across the Pacific — over a million years ago.

But Tim P. Denham, an archaeologist at the Australian National University who was not involved in the study, found this scenario hard to swallow.

It would suggest that the wild ancestors of sweet potatoes spread across the Pacific and were then domesticated many times over — yet wound up looking the same every time. “This would seem unlikely,” he said.

Dr. Kistler argued that it was still possible that Pacific Islanders voyaged to South America and returned with the sweet potato.

A thousand years ago, they might have encountered many sweet potato varieties on the continent. When Europeans arrived in the 1500s, they likely wiped out much of the crop’s genetic diversity.

As a result, Dr. Kistler said, the surviving sweet potatoes of the Pacific only seem distantly related to the ones in the Americas. If the scientists had done the same study in 1500, Pacific sweet potatoes would have fit right in with other South American varieties.

Dr. Kistler was optimistic that the sweet potato debate would someday be settled. The world’s herbariums contain a vast number of varieties that have yet to be genetically tested.

“There are more than we could look at in a lifetime,” Dr. Kistler said.

For his part, Mr. Muñoz-Rodríguez plans on searching for more wild sweet potato relatives in Central America, hoping to get more clues to how exactly a thin-rooted weed gave rise to an invaluable crop.

Working out the history of crops like this could do more than satisfy our curiosity about the past. Wild plants hold a lot of genetic variants lost when people domesticated crops.

Researchers may find plants they can hybridize with domesticated sweet potatoes and other crops, endowing them with genes for resistance to diseases, or for withstanding climate change.

Caption1 The distribution of the sweet potato plant has baffled scientists. How could the plant arise from a wild ancestor in the Americas and wind up on islands across the Pacific? Karsten Moran for The New York Times

Caption2 Different varieties of sweet potato on display at the International Potato Center in Lima, Peru. The sweet potato originated in the Americas and spread across the globe. Robert Scotland

Archaeologists near the Swiss city of Basel are trying to definitively establish if mysterious shafts discovered at Switzerland’s extensive Augusta Raurica site in 2013 could have been ancient refrigerators.

The Romans used shafts like the four-metre deep examples at Augusta Raurica – some 20 kilometres from Basel – as cool stores during summer.

The shafts were filled with snow and ice during winter and then covered with straw to keep the space cool well into the summer months. This then allowed for everything from cheese to wine – and even oysters – to be preserved during warm weather.

Now a team lead by Peter-Andrew Schwarz from the University of Basel is attempting, for the third time, to demonstrate that the Augusta Raurica shafts were indeed used as fridges, Swiss news agency SDA/ATS reports.

A first attempt to recreate the ancient cool box failed after archaeologists at the dig filed the shaft with snow all in one go. But that experiment showed temperatures in the shaft were above freezing point even in winter.

The second try was more successful: the shaft was gradually filled with snow and ice blocks were placed inside as well. Using these methods, snow remained until June.

Now, however, researchers plan to use methods developed by the so-called ‘nevaters’ or ice-makers on the Spanish island of Majorca. This will see Schwarz and his team placing 20–30-centimetre-thick layers of snow into the shaft. These individual layers will then be compacted down with a straw cover placed on top of each one.

“With this method, people in Majorca could keep food cool in summer before the arrival of electric fridges,” Schwarz told regional daily Basler Zeitung in 2017.

Work at the site of the ‘fridge’ will continue until Friday with the dig open to the public.

The experiment won’t prove that the mysterious shaft was actually a Roman fridge but will show that this is possible, Schwarz told the SDA/ATS news agency.